Allow the extra_args flags to suport flags with commas in them.

If something ends with '\' then join it with the next arg.

Tested: bazel build //some/opt/target --//xls/common/config:extra_opt_args=--alsologtostderr,--vmodule=pass_base=2\\,narrowing_pass=4
PiperOrigin-RevId: 815777765

Author: allight

xls/build_rules/xls_codegen_rules.bzl

@@ -22,6 +22,7 @@ load(
     "//xls/build_rules:xls_common_rules.bzl",
     "append_default_to_args",
     "args_to_string",
+    "fixup_extra_args",
     "get_input_infos",
     "get_output_filename_value",
     "get_runfiles_for_xls",
@@ -431,7 +432,7 @@ def xls_ir_verilog_impl(ctx, src, conv_info):
     final_args += " --scheduling_options_used_textproto_file={}".format(
         sched_config_textproto_file.path,
     )
-    for v in ctx.attr._extra_codegen_flags[BuildSettingInfo].value:
+    for v in fixup_extra_args(ctx.attr._extra_codegen_flags[BuildSettingInfo].value):
         final_args += " " + v
 
     if "local" in ctx.attr.tags:

xls/build_rules/xls_common_rules.bzl

@@ -332,3 +332,47 @@ def get_transitive_built_files_for_xls(ctx, additional_target_list = []):
         return None
 
     return transitive_built_files
+
+def _count_trailing(full, piece):
+    """Counts the number of trailing occurrences of 'piece' in 'full'.
+
+    Args:
+      full: The string to search within.
+      piece: The character or substring to count at the end of 'full'.
+
+    Returns:
+      The number of times 'piece' appears at the end of 'full'.
+    """
+    i = 0
+    for x in reversed(full):
+        if x != piece:
+            return i
+        i += 1
+    return i
+
+def fixup_extra_args(inp):
+    """Fixes up extra arguments by concatenating those ending in a single backslash.
+
+    Iterates through the input list of strings. If an element ends with a single
+    backslash, it is concatenated with the *next* element using a comma.
+    Elements ending with double backslashes are treated as normal.
+
+    Example:
+      fixup_extra_args(["--a=1", "--b=c=4\\", "d=2", "--c=3"]) -> ["--a=1", "--b=c=4,d=2", "--c=3"]
+      fixup_extra_args(["--a=\\", "--b=\\", "2"]) -> ["--a=, --b=,2"]
+      fixup_extra_args(["--a=\\\\", "--b=2"]) -> ["--a=\\\\", "--b=2"]
+
+    Args:
+      inp: A list of strings representing command line arguments.
+
+    Returns:
+      A list of strings with backslash-escaped arguments concatenated.
+    """
+    res = []
+    for v in inp:
+        if not res or _count_trailing(full = res[-1], piece = "\\") % 2 == 0:
+            # No previous element or last element doesn't end with an escaped '\'.
+            res.append(v)
+        else:
+            res[-1] = res[-1][:-1] + "," + v
+    return res

xls/build_rules/xls_ir_rules.bzl

@@ -22,6 +22,7 @@ load(
     "append_cmd_line_args_to",
     "append_default_to_args",
     "args_to_string",
+    "fixup_extra_args",
     "get_original_input_files_for_xls",
     "get_output_filename_value",
     "get_runfiles_for_xls",
@@ -319,7 +320,7 @@ def _optimize_ir(ctx, src, original_input_files):
         outs.append(pprof_file)
         extra_outs.append(pprof_file)
     runfiles = get_runfiles_for_xls(ctx, [], [src.ir_file] + ram_rewrite_files + debug_src_files + original_input_files)
-    for v in ctx.attr._extra_opt_flags[BuildSettingInfo].value:
+    for v in fixup_extra_args(ctx.attr._extra_opt_flags[BuildSettingInfo].value):
         args.add(v)
     ctx.actions.run(
         outputs = outs,